Fluid and gas separator

ABSTRACT

A method of separating gas from a fluid mixture in a production stream of a well where the method includes using an outer tube and an inner tube positioned concentrically with the outer tube to separate gas and liquid from a mixture. The production stream is directed through the outer tube and into a space between a well casing of the well and the outer tube where gas in the production stream can separate from fluid in the production stream. The separated fluid is then directed through the inner tube to a pump.

CROSS REFERENCE TO RELATED INFORMATION

This application is a continuation of U.S. patent application Ser. No.16/828,439, filed Mar. 24, 2020, titled Fluid and Gas Separator, nowU.S. Pat. No. 11,098,571; which is a continuation application of U.S.patent application Ser. No. 16/251,813, filed Jan. 18, 2019, titledFluid and Gas Separator, now U.S. Pat. No. 10,605,065 the contents ofwhich are hereby incorporated herein in its entirety.

TECHNICAL FIELD

The present disclosure is directed to an apparatus and method forpetroleum producing and injection wells and more particularly to theseparation of gas and liquid from a hydrocarbon production stream.

BACKGROUND OF THE INVENTION

Petroleum wells can be naturally flowing, injecting or can be producedby any means of artificial lift. Referring to FIG. 1, a diagram of atypical sucker rod pump used in oil wells is described. Well (10) mayinclude a well bore (11) and a pump assembly (12). Pump assembly (12)may be formed by a motor (13) that supplies power to a gear box (14).Gear box (14) is operable to reduce the angular velocity produced bymotor (13) and to increase the torque relative to the input of motor(13). The input of motor (13) may be used to turn crank (15) and liftcounter weight (16). As crank (15) is connected to walking beam (17) viapitman arm (18), walking beam (17) may pivot and submerge plunger (19)in well bore (11) using bridle (20) connected to walking beam (18) byhorse head (21). Walking beam (17) may be supported by sampson post(22).

As shown in FIGS. 1-2, well bore (11) may include casing (23) and tubing(24) extending inside casing (23). Sucker rod (25) may extend throughthe interior of tubing (24) to plunger (19). At the bottom of well bore(11), in oil bearing region (26), casing (23) may include perforations(27) that allow hydrocarbons and other material to enter annulus (28)between casing (23) and tubing (24). Gas may be permitted to separatefrom the liquid products and travel up the annulus where it is captured.Liquid well products may collect around pump barrel (29), which containsstanding valve (30), as shown in FIGS. 3A-3B. Plunger (19) may includetraveling valve (31). During the down stroke of the plunger (FIG. 3B),traveling valve (31) may be opened and product in the pump barrel (29)may be forced into the interior of tubing (24). When the pump begins itsupstroke (FIG. 3A), traveling valve (31) may be closed and the materialin the tubing may be forced up the tubing by the motion of plunger (19).Also, during the upstroke, standing valve (30) may be opened andmaterial may flow from the annulus in the oil bearing region and intothe pump barrel.

As can be seen from FIG. 1, where the product flowing into the well borecontains entrained and free gas, that gas can enter the pump and reducethe volumetric efficiency of the pump. For instance, the hydrocarbonproduction stream can include both liquid and gaseous products that area natural byproduct of the producing wells. As hydrocarbons and waterflow through the formation, gases can travel in the flow stream eitherseparate from the liquid products or dissolved within the liquidproducts. The gases are carried into the production tubing and can causeproblems with artificial lifting mechanisms, such as rod pumps, byreducing the volumetric efficiency of the pump.

Gas interference occurs in situations when the pump is filling with aconsiderable amount of free gas that is not separated before enteringthe pump. If the amount of free gas entering the pump can be reduced,the volumetric efficiency of the pump can be improved, or the total pumpcapacity can be increased.

BRIEF SUMMARY OF THE INVENTION

A separator for separating gas from a fluid mixture in a productionstream in a producing hydrocarbon well is described. The separator maycomprise an outer tube defining an outer conduit extending from a lowerend to an upper end of the outer tube. The outer conduit may comprise alower portion and an upper portion having a larger outer diameter thanthe lower portion. The outer conduit may comprise a bell portionextending outwardly between the lower portion and the upper portion. Theseparator may further comprise an inner tube positioned concentricallywith the outer tube, the inner tube defining an inner conduit extendingfrom a lower end to an upper end of the inner tube. The inner conduitmay comprise a lower portion and an upper portion having a larger outerdiameter than the lower portion. The inner conduit may comprise a bellportion extending outwardly between the lower portion and the upperportion.

A separator assembly for use within a well bore is described. Theseparator assembly may comprise a casing defining an annulus and apacker disposed within the annulus of the casing. A portion of thepacker may be positioned adjacent to an interior surface of the casing.The separator assembly may further comprise a separator disposed withinthe annulus of the casing above the packer. The separator may comprisean outer tube and an inner tube positioned concentrically with the outertube. The outer tube may define an outer conduit extending from a lowerend to an upper end of the outer tube. The outer conduit may comprise alower portion and an upper portion having a larger outer diameter thanthe lower portion. The outer conduit may comprise a bell portionextending outwardly between the lower portion and the upper portion. Theinner tube may define an inner conduit extending from a lower end to anupper end of the inner tube. The inner conduit may comprise a lowerportion and an upper portion having a larger outer diameter than thelower portion. The inner conduit may comprise a bell portion extendingoutwardly between the lower portion and the upper portion.

A method for separating gas from a fluid mixture in a production streamin a well is described. The method may comprise the steps of directingthe production stream into an outer tube of a separator; reducing thefluid velocity of the production stream within the outer tube; directingthe production stream out of the outer tube into a space between a wellcasing of the well and the outer tube where gas in the production streamcan separate from fluid in the production stream; directing theseparated fluid of the production stream into an inner tube of theseparator; reducing the fluid velocity of the separated fluid of theproduction stream within the inner tube; and drawing the separated fluidof the production stream through the inner tube.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present invention. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the invention as set forth in the appendedclaims. The novel features which are believed to be characteristic ofthe invention, both as to its organization and method of operation,together with further objects and advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. It is to be expressly understood, however, thateach of the figures is provided for the purpose of illustration anddescription only and is not intended as a definition of the limits ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference isnow made to the following descriptions taken in conjunction with theaccompanying drawings, in which:

FIG. 1 depicts a diagram of a prior art petroleum producing well showingan existing sucker rod pump assembly to provide artificial lift.

FIG. 2 depicts a sectional view of the well string shown in FIG. 1.

FIG. 3A depicts a detail view of the plunger portion of the well of FIG.1 showing the up stroke.

FIG. 3B depicts a detail view of the plunger portion of the well of FIG.1 showing the down stroke.

FIG. 4 depicts a perspective view of an exemplary embodiment of a gasseparator for use within a petroleum producing well.

FIG. 5 depicts a cross-sectional view of the separator of FIG. 4.

FIG. 6 depicts a cross-sectional view of the separator of FIG. 4 showinga flow path through the separator.

FIG. 7 depicts a detail view of the flow path of the separator in FIG. 6at a bottom portion of the separator.

FIG. 8 depicts a detail view of the flow path of the separator in FIG. 6at a top portion of the separator.

FIG. 9 depicts a diagram of an embodiment of a separator assemblycomprising the separator of FIG. 4 assembled with a packer and disposedwithin a casing of a well bore.

FIG. 10 depicts a diagram of a separator assembly employing an alternateshroud configuration and assembled with other exemplary tools.

DETAILED DESCRIPTION OF THE INVENTION

A fluid and gas separator for a hydrocarbon producing well providesmechanisms for both reducing the amount of gas entrained in a liquidproduct, including oil and/or water, and separating that free gas fromthe liquid product. The mechanism uses a packer type separator to createan artificial sump for the pump. Any type of artificial lift applicableto any producing oil well may be used, such as a sucker rod pump, rodpumping, electric submersible pumps, progressive cavity, and othermethods.

Referring now to FIGS. 4-5, a fluid and gas separator (100) is shown foruse in a hydrocarbon producing well. The separator (100) comprises anouter tube (103) and an inner tube (113) positioned within the outertube (103) such that the outer and inner tubes (103, 113) areconcentrically aligned along a longitudinal axis. The outer tube (103)defines an outer conduit (121) extending from a lower end (120) of theseparator (100) to an upper end (122) of the separator (100). A threadedportion (102, 104) may be provided on each of the lower and upper ends(120, 122). These threaded portions (102, 104) may be used toselectively couple the separator (100) with other tooling, as will bedescribed in more detail below.

In the illustrated embodiment, the outer conduit (121) comprises a lowerportion (106) and an upper portion (108), wherein the upper portion(108) has a larger diameter than the lower portion (106). A bell portion(118) is positioned between the upper portion (108) and the lowerportion (106) of the outer conduit (121) such that the bell portion(118) forms a tapered wall extending outwardly between the lower andupper portions (106, 108). In some versions, the upper portion (108) mayhave an outer diameter of about 1.9 to 2.625 inches and the lowerportion (106) may have an outer diameter of about 0.75 to 2. inches, butother suitable dimensions may be used as appropriate for the well bore.The separator (100) may also have a length of about 40 feet, but othersuitable dimensions may be used, particularly standardized lengths forwell bore tools. The outer tube (103) further comprises a plurality ofslots (110) extending through the upper portion (108) from the outerconduit (121) to an exterior surface of the outer tube (103). In theillustrated embodiment, the slots (110) have a rectangular shapeextending longitudinally along the upper portion (108), but any othersuitable profiles may be used.

Referring to FIGS. 6-8, a fluid mixture including gas may enter theouter conduit (121) at the lower end (120) of the separator (100), asshown by arrows (130). The fluid and gas may then flow through the lowerportion (106) of the outer conduit (121), through the bell portion(118), and up to the upper portion (108) of the outer conduit (121) bymeans of an artificial lift mechanism, as shown by arrows (131). As thefluid and gas passes through the bell portion (118) of the outer conduit(121), the velocity of the fluid and gas may decrease as it flows fromthe smaller diameter of the lower portion (106) to the larger diameterof the upper portion (108). The fluid and gas may then exit the outerconduit (121) through the plurality of slots (110). Accordingly, thebell portion (118) may aid in slowing the velocity of the fluid and gasto reduce turbulence as the fluid and gas exit through the slots (110).In some versions, the bell portion (118) is positioned about 35 feetabove the lower end (120) of the separator (100). When the fluid and gasexit through the slots (110), to area between the outer tube (103) and acasing, the gas may be permitted to separate from the fluid mixturebecause the gas is less dense than the fluid mixture. Accordingly, thefree gas may rise, as shown by arrows (132), where it may be capturedbefore reaching the pump. The separated fluid mixture may then fall dueto gravitational forces toward the lower end (120) of the separator(100), as shown by arrows (134).

The lower portion (106) of the outer tube (103) comprises a shroud (112)positioned adjacent to the lower end (120) of the outer tube (103) ofthe lower portion (106). The shroud (112) comprises a flange (114)extending outwardly from the outer tube (103) that defines an opening(124). As best seen in FIG. 5, the flange (114) is positioned such thatthe opening (124) extends downwardly through the flange (114),substantially parallel relative to the outer tube (103), to a loweropening (126) of the inner tube (113). The lower portion of the innertube (113) may be curved outwardly to adjoin the opening (124) of theflange (114). Accordingly, the separated fluid may descend from theupper portion (108) of the outer tube (103) to the opening (124) of theflange (114) to enter the inner tube (113). The shroud (112) is therebypositioned to as a cup to capture the separated fluid and to cover thelower opening (126) of the inner tube (113) to prevent any leaked gasfrom entering the inner tube (113).

As best seen in FIGS. 5-6, the inner tube (113) defines an inner conduit(115) extending from the lower opening (126) of the inner tube (113) tothe upper end (122) of the separator (100). In the illustratedembodiment, the inner conduit (115) comprises a lower portion (116) andan upper portion (117) corresponding to the outer conduit (121), whereinthe upper portion (117) has a larger diameter than the lower portion(116). A bell portion (119) is positioned between the upper portion(117) and the lower portion (116) of the inner conduit (115) such thatthe bell portion (119) forms a tapered wall extending outwardly betweenthe lower and upper portions (116, 117). In some versions, the upperportion (117) may have a diameter of about 1.9 to 2.625 inches and thelower portion (116) may have a diameter of about 0.75 to 1.3 inches, butother suitable dimensions may be used depending on well bore size andflow rates.

The separated fluid may collect in the opening (124) of the shroud (112)and enter the inner conduit (115) at the lower opening (126) of theinner tube (113), where the separated fluid may be redirected upwardthrough the inner conduit (115) by means of an artificial liftmechanism, as shown by arrows (135). The separated fluid may then flowthrough the lower portion (116) of the inner conduit (115), through thebell portion (119), and up to the upper portion (117) of the innerconduit (115), shown by arrows (136). The separated fluid may then exitthe inner conduit (115) through the opening at the upper end (122) ofthe separator (100), where it may be collected by the pump. As theseparated fluid passes through the bell portion (119) of the innerconduit (115), the velocity of the separated fluid may decrease as itflows from the smaller diameter of the lower portion (116) to the largerdiameter of the upper portion (117) to reduce emulsions prior to pumpentry. The bell portion (119) of the inner conduit (115) may also bepositioned at about 35 feet from the lower end (120) of the separator(100). Accordingly, the separator (100) may deliver fluid free of gas tothe pump, which may improve the volumetric efficiency of the pump and/orincrease the total pump capacity. Still other suitable configurationsfor the separator (100) will be apparent to one with ordinary skill inthe art in view of the teachings herein.

A separator assembly (150) is shown in FIG. 9 comprising the separator(100) described above assembled with a packer (200) and disposed withina casing (123) of a well bore. For instance, the lower end (120) of theseparator (100) may be coupled with a packer (200), such as bythreadably coupling the threaded portion (104) of the separator (100)with the packer (200). This may prevent the packer (200) from gettingstuck in the casing (123). In the illustrated embodiment, the packer(200) comprises a plurality of divertor cups (204) extending outwardlyfrom a body (202) of the packer (200) to an interior surface of thecasing (123). The cups (204) may thereby reduce or prevent any materialfrom leaking around the exterior surface of the packer (200) to theseparator (100). While two cups (204) are shown, any other suitablenumber of cups (204) may be used, such as four. A conduit (208) thenextends through the body (202) of the packer (200). Fluid and gas maythereby flow from an oil-bearing region of the well-bore and through theconduit (208) of the packer (200). The packer (200) may thereby directthe production stream of the well to the separator (100).

The fluid and gas may then flow from the packer (200) into the outerconduit (121) of the outer tube (103) at the lower end (120) of theseparator (100) by means of an artificial lift mechanism. The fluid andgas may flow through the lower portion (106) of the outer conduit (121),through the bell portion (118), and up to the upper portion (108) of theouter conduit (121). As the fluid and gas passes through the bellportion (118) of the outer conduit (121), the velocity of the fluid andgas may decrease as it flows from the smaller diameter of the lowerportion (106) to the larger diameter of the upper portion (108). Thefluid and gas may then exit the outer conduit (121) through theplurality of slots (110) in the upper portion (108) of the outer tube(103). When the fluid and gas exit the outer conduit (121), the gas maybe permitted to rise in the area between the outer tube (103) and thecasing (123) and the fluid may fall due to gravitational forces suchthat the gas is separated from the production stream. The separatedfluid may then flow toward the lower end (120) of the separator (100).

The separated fluid may collect within opening (124) of the shroud (112)and may flow into the inner tube (113). The separated fluid may therebyenter the inner conduit (115) at the lower opening (126) of the innertube (113), where the separated fluid may be redirected upward throughthe inner conduit (115) by means of an artificial lift mechanism. Theseparated fluid may then flow through the lower portion (116) of theinner conduit (115), through the bell portion (119), and up to the upperportion (117) of the inner conduit (115). As the separated fluid passesthrough the bell portion (119) of the inner conduit (115), the velocityof the separated fluid may decrease as it flows from the smallerdiameter of the lower portion (116) to the larger diameter of the upperportion (117). The separated fluid may then exit the inner conduit (115)through the upper end (126) of the separator (100) to the pump. Stillother suitable methods for operating the separator (100) will beapparent to one with ordinary skill in the art in view of the teachingsherein.

Accordingly, the separator (100) allows the separated fluid to moreefficiently flow to the pump. For instance, to provide a total fluidamount of about 400 through the pump in an about 4.5-inch diametercasing, the outer diameter of the lower portion (106) may provide adownward fluid velocity of about 0.4 and the outer diameter of the upperportion (108) may provide a downward fluid velocity of about 0.49feet/second. To provide a total fluid amount of about 400 through thepump in an about 5.5-inch diameter casing, the outer diameter of thelower portion (106) may provide a downward fluid velocity of about 0.28and the outer diameter of the upper portion (108) may provide a downwardfluid velocity of about 0.32 feet/second. The smaller outer diameter ofthe lower portion (106) may also allow a user to maximize the annulus ofthe given well bore by increasing the size of the annulus, which maycorrelate to improved downward fluid velocities and provide a largerflow area to the pump for an improved efficiency of about 20 percent.

Referring now to FIG. 10 an embodiment of a separator (1000) accordingto the concepts described herein is shown in relation to other stringelements that may be employed with separator (1000). While a certainconfiguration is shown it is only illustrative of the types ofconfigurations that may be used and is not intended to be limiting. Theseparator (1000) operates as described above with respect to FIG. 9. Asdescribed, separator includes upper portion 1008 and lower portion 1006joined at bell portion (1018). The separator (1000) also illustrates analternative shroud (1012) embodiment. Shroud (1012) surrounds the entirelower portion 1006, including the fluid intake (not shown). Shroud (1012is sealed at the bottom but open at the top such that gas flowing up thewell is directed by shroud (1012) around and away from the intake tolower portion (1006).

FIG. 10 further shows separator (1000) connected to seating nipple 1100at the joint to allow connection to the well string or other downholetools. Packer 1200 extends between separator (1000) and the innersurface of the casing as described. Below separator (1000) other toolsmay be connected, such as desander (1102) which is used to remove sandfrom the well fluid. Mud joints (1104) can be used collect sand removedfrom the well fluid and bull plug (1106 seals the bottom of the wellstring inside the casing.

While the present invention has been described with reference to a rodpumped well, the concepts described herein may be applied to any type ofartificial lift system usable in any producing oil well, such as asucker rod pump, rod pumping, electric submersible pumps, progressivecavity, and other methods.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims. Moreover, thescope of the present application is not intended to be limited to theparticular embodiments of the process, machine, manufacture, compositionof matter, means, methods and steps described in the specification. Asone of ordinary skill in the art will readily appreciate from thedisclosure of the present invention, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the present invention.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps.

What is claimed is:
 1. A method for separating gas from fluid in aproduction stream in a well, the method comprising the steps of:directing the production stream into an outer tube of a separator;reducing the fluid velocity of the production stream within the outertube; directing the production stream out of the outer tube into a spacebetween a well casing of the well and the outer tube where gas in theproduction stream can separate from fluid in the production stream;directing the separated fluid of the production stream into an innertube of the separator; reducing the fluid velocity of the separatedfluid of the production stream within the inner tube; drawing theseparated fluid of the production stream through the inner tube; anddelivering the separated fluid of the production stream from the innertube to a pump.
 2. The method of claim 1, further comprising using apacker to direct the production stream into the separator.
 3. The methodof claim 2, further comprising preventing any gas leaked around thepacker from entering the inner tube.
 4. The method of claim 1, whereinreducing the fluid velocity of the production stream within the outertube comprises increasing an outer diameter of the outer tube to therebyincrease the flow area of the outer tube.
 5. The method of claim 1,wherein reducing the fluid velocity of the separated fluid of theproduction stream within the inner tube comprises increasing an outerdiameter of the inner tube to thereby increase the flow area of theinner tube.
 6. A method for separating gas from fluid in a productionstream in a well, the method comprising the steps of: directing theproduction stream into an outer tube of a separator; reducing the fluidvelocity of the production stream within the outer tube; directing theproduction stream out of the outer tube into a space between a wellcasing of the well and the outer tube where gas in the production streamcan separate from fluid in the production stream; directing theseparated fluid of the production stream into an inner tube of theseparator, and using a shroud to direct the separated fluid from theouter tube and to prevent well gasses from entering the inner tube;reducing the fluid velocity of the separated fluid of the productionstream within the inner tube; and drawing the separated fluid of theproduction stream through the inner tube.
 7. A method of separating anoil and gas mixture made up of oil and gas within a well bore, the wellbore defined by a casing, the method comprising: directing the oil andgas mixture into an outer tube defining an outer conduit extending froma lower end to an upper end of the outer tube, wherein the outer conduitcomprises a lower portion and an upper portion having a larger outerdiameter than the lower portion, wherein the outer conduit comprises abell portion extending outwardly between the lower portion and the upperportion; reducing a velocity of the oil and gas mixture as the oil andgas mixture passes from the lower portion to the upper portion of theouter conduit; directing the oil and gas to pass from inside the outertube to a space between the outer tube and the casing though a pluralityof slots in the upper portion of the outer conduit, wherein the gasrises up the casing and the oil flows down the space between the outertube and the casing; and directing the oil into an inner portion of aninner tube positioned concentrically within the outer tube through anintake in the outer tube below the plurality of slots, wherein the innertube defines an inner conduit extending from a lower end to an upper endof the inner tube, wherein the inner conduit comprises a lower portionand an upper portion having a larger outer diameter than the lowerportion, wherein the inner conduit comprises a bell portion extendingoutwardly between the lower portion and the upper portion.
 8. The methodof claim 7, wherein the plurality of slots are staggered along the upperportion of the outer tube.
 9. The method of claim 7, wherein theplurality of slots assist in separating the gas from the oil and gasmixture when the oil and gas mixture exits through the plurality ofslots.
 10. The method of claim 9 further comprising allowing theseparated oil to flow from a lower end of the inner conduit to an upperend of the inner conduit, wherein the intake is at the lower end of theinner conduit and is open to receive the separated oil.
 11. The methodof claim 10, wherein the larger outer diameter of the upper portion ofthe inner conduit defines a larger flow area in the upper portionrelative to the lower portion, allowing a fluid velocity of theseparated oil to decrease when the separated oil flows from the lowerportion to the upper portion of the inner conduit.
 12. The method ofclaim 7, wherein the outer tube comprises a shroud positioned about theouter tube adjacent to the lower end of the outer tube, wherein theshroud covers the intake and prevents gasses from entering theseparator.
 13. The method of claim 12, wherein an opening of the shroudis positioned upward to collect separated oil exiting from the outertube.
 14. The method of claim 12, wherein the shroud is positioned tocover the lower end of the inner tube.
 15. The method of claim 7,wherein the lower end and the upper end of the outer tube each comprisea threaded portion.
 16. The method of claim 7, wherein the lower end ofthe outer tube is couplable with a packer.
 17. The method of claim 7,further comprising positioning the separator within the casing of thewell bore.